MatrixStack persMatrix = new MatrixStack();
persMatrix.perspective( 60.0f, 1.0f, zNear, zFar );
glUseProgram( smoothInterp.theProgram );
glUniformMatrix4( smoothInterp.cameraToClipMatrixUnif, false,
persMatrix.top().fillAndFlipBuffer( mat4Buffer ) );
glUseProgram( linearInterp.theProgram );
glUniformMatrix4( linearInterp.cameraToClipMatrixUnif, false,
persMatrix.top().fillAndFlipBuffer( mat4Buffer ) );
glUseProgram( 0 );
}